Fully infiltrated rotary drill bit

ABSTRACT

A fully infiltrated rotary drill bit having a bit body that includes at least one particle-matrix composite material having a particle material composition and a binder material having a binder material composition that differs from the particle material composition. The particle material composition has a particle material melting temperature and the binder material composition has a binder melting temperature that is lower than the particle material melting temperature.

CROSS REFERENCE TO RELATED PATENT APPLICATION

This application claims priority to U.S. Provisional Application No. 61/992,654 filed May 13, 2014, which is herein incorporated by reference in its entirety.

FIELD OF THE INVENTION

This invention relates to a rotary drill bit. More specifically, this invention relates to a fully infiltrated rotary drill bit.

BACKGROUND OF THE INVENTION

Rotary drill bits are commonly used for subterranean drilling of bore holes or wells. Many types of drills and associated methods have been employed for such drilling. A common type of drilling employs a rotary drill bit affixed to the end of a drill string. Rotary drill bits typically include a plurality of cutting elements secured to a face region of a bit body. The drill string includes tubular pipe and equipment segments that couple the drill bit located at the bottom of the borehole to other drilling equipment at the surface. A rotary table or top drive may be used for rotating the drill string and the drill bit within the borehole. Alternatively, the shank of the drill bit may be coupled directly to the drive shaft of a down-hole motor, which then may be used to rotate the drill bit.

Rotary drill bits generally have either a disk shape or a substantially cylindrical shape, particularly on the cutting end that houses the cutting elements. The cutting elements each have a cutting surface that is generally made from a hard, super-abrasive material, such as polycrystalline diamond, often in the form of a substantially circular end surface of the element, and are often referred to as “polycrystalline diamond compact” (PDC) cutters. Many forms of such bits are possible; however, the cutting elements are often fabricated separately from the bit body and then fixed into pockets formed in its outer surface. The cutting elements may be fixed in any suitable manner, such as, for example, by use of a bonding material, including various adhesives or, more typically, various braze alloys. The bit body is secured to a hardened steel shank having an American Petroleum Institute (API) thread connection for attaching the drill bit to the drill string. In use, the cutting elements and their cutting surfaces are placed in contact with the earth formation to be drilled. As the bit is rotated, the cutting elements progressively shear away the surface of the underlying formation to form the borehole.

The bit body of a rotary drill bit may be formed from steel; however, such bit bodies experience abrasive wear, the rate of which can vary significantly as a function of the drilling environment. In order to reduce the wear and extend their life, bit bodies have also been made from particle-matrix composite materials.

Particle-matrix composite bit bodies have been fabricated in graphite molds with machined cavities. Additional fine features may be added to the cavity of the graphite mold by hand-held tools. Inserts or cores made from sand, clay or other materials may also be used to obtain the desired configuration of some features of the bit body. Where necessary, preform elements or displacements (which may be made from any suitable material, including ceramic components, graphite components, or resin-coated sand compact components) may be positioned within the mold and used to define various features, including internal passages, cutting element pockets, junk slots, and other external topographic or internal features of the bit body. The cavity of the graphite mold is filled with hard particulate carbide material (such as tungsten carbides, titanium carbides, tantalum carbides, etc.). The preformed steel blank is then positioned in the mold at the appropriate location and orientation, which typically is at least partially submerged in the particulate carbide material within the mold.

The mold then may be vibrated or the particles otherwise packed to increase the packing density of the carbide powder and produce the powder form. A matrix material, such as a copper-based alloy, is melted and introduced to the carbide powder so as to cause infiltration of the powder form by the molten matrix material. The mold and bit body are allowed to cool to solidify the matrix material and bond the steel blank to the particle-matrix composite material forming a crown. The mold and any displacements are removed from the bit body. Destruction of the graphite mold typically is required to remove the bit body.

After the bit body has been removed from the mold, the bit body is conventionally secured to the steel shank. Thread forms may be machined on an exposed surface of the steel blank to provide a threaded connection between the bit body and the steel shank.

While steel blanks afford a generally acceptable means of connecting the steel shank and the bit body, shifting of the blank in the mold during infiltration can occur resulting in misalignment of the blank with respect to the bit body, thereby causing the bit body to be unusable, or requiring additional machining or other rework of the bit body. Further, introduction of the blank as an additional component requires that it be degreased or otherwise cleaned prior to infiltration to ensure a metallurgical bond between the blank and the metal matrix. Still further, depending on the material used for the blank, interaction between the blank and matrix material may lead to the formation of phases at the interface between them that can result in crack formation and propagation during use of the bit.

While bit bodies that include particle-matrix composite materials offer significant advantages over all-steel bit bodies in terms of abrasion and erosion-resistance, the lower strength and toughness of such bit bodies limit their use in certain applications. Improvement of the particle-matrix composite to increase the toughness, strength or other properties would increase the applications where such bit bodies may be used.

SUMMARY

The invention relates to a rotary drill bit comprising a bit body that comprises at least one particle-matrix composite material and a binder material. In one aspect, each of the at least one particle-matrix composite material has a particle material composition, which also has a particle material melting temperature. In another aspect, the binder material has a binder material composition that differs from the particle material composition. In this aspect, the binder material composition has a binder material melting temperature that is lower than the particle material melting temperature.

In a further aspect, at least one of the particle-matrix material composition and the binder material composition can be comprised of a matrix material and a plurality of hard particles dispersed throughout the matrix materials.

When formed, the binder material is infiltrated within and substantially encapsulates particle-matrix composite material to form a substantially uniform particle grain microstructure. In this aspect, it is contemplated that the particle-matrix composite material is substantially non-melted in the formation process of the drill bit.

DETAILED DESCRIPTION OF THE FIGURES

These and other features of the preferred embodiments of the invention will become more apparent in the detailed description in which reference is made to the appended drawings wherein:

FIG. 1 is a schematic partial cross-sectional view of an exemplary embodiment of a rotary drill bit disclosed herein.

FIG. 2 is a schematic partial cross-sectional view of a second exemplary embodiment of a rotary drill bit disclosed herein.

The illustrations presented herein, are not meant to be actual views of any particular material, apparatus, system, or method, but are merely idealized representations of that which is disclosed herein. Additionally, elements common between figures may retain the same numerical designation.

DETAILED DESCRIPTION OF THE INVENTION

The present invention can be understood more readily by reference to the following detailed description, examples, drawing, and claims, and their previous and following description. However, before the present devices, systems, and/or methods are disclosed and described, it is to be understood that this invention is not limited to the specific devices, systems, and/or methods disclosed unless otherwise specified, as such can, of course, vary. It is also to be understood that the terminology used herein is for the purpose of describing particular aspects only and is not intended to be limiting.

The following description of the invention is provided as an enabling teaching of the invention in its best, currently known embodiment. To this end, those skilled in the relevant art will recognize and appreciate that many changes can be made to the various aspects of the invention described herein, while still obtaining the beneficial results of the present invention. It will also be apparent that some of the desired benefits of the present invention can be obtained by selecting some of the features of the present invention without utilizing other features. Accordingly, those who work in the art will recognize that many modifications and adaptations to the present invention are possible and can even be desirable in certain circumstances and are a part of the present invention. Thus, the following description is provided as illustrative of the principles of the present invention and not in limitation thereof.

As used throughout, the singular forms “a,” “an” and “the” include plural referents unless the context clearly dictates otherwise. Thus, for example, reference to “a particle-matrix composite material” can include two or more such particle-matrix composite material unless the context indicates otherwise.

Ranges can be expressed herein as from “about” one particular value, and/or to “about” another particular value. When such a range is expressed, another aspect includes from the one particular value and/or to the other particular value. Similarly, when values are expressed as approximations, by use of the antecedent “about,” it will be understood that the particular value forms another aspect. It will be further understood that the endpoints of each of the ranges are significant both in relation to the other endpoint, and independently of the other endpoint.

As used herein, the terms “optional” or “optionally” mean that the subsequently described event or circumstance may or may not occur, and that the description includes instances where said event or circumstance occurs and instances where it does not.

As used herein, the term “[metal]-based alloy” (where [metal] is any metal) means commercially pure [metal] in addition to metal alloys wherein the weight percentage of [metal] in the alloy is greater than the weight percentage of any other component of the alloy. Where two or more metals are listed in this manner, the weight percentage of the listed metals in combination is greater than the weight percentage of any other component of the alloy.

As used herein, the term “material composition” means the chemical composition and microstructure of a material. In other words, materials having the same chemical composition but a different microstructure are considered to have different material compositions.

As used herein, the term “tungsten carbide” means any material composition that contains chemical compounds of tungsten and carbon in any stoichiometric or non-stoichiometric ratio or proportion, such as, for example, WC, W₂C, and combinations of WC and W₂C. Tungsten carbide includes any morphological form of this material, for example, cast tungsten carbide, sintered tungsten carbide, monocrystalline tungsten carbide, and macrocrystalline tungsten carbide.

An exemplary embodiment of an earth-boring rotary drill bit 10 having a bit body 20 is illustrated in FIG. 1. The bit body 20 has a distal cutting region 22 configured to engage a subterranean earth formation and a proximal treaded region 24 configured to be selectively coupled to a drill sting. In one aspect, the proximal treaded region defines an open internal cavity 26 extending along a longitudinal axis of the bit body. It is further contemplated that a helical thread 28, which is configured to matingly engage and attach to the drill string, can be formed on an interior wall surface of the open internal cavity. As contemplated in the invention, the bit body is fully infiltrated and, as such, will not be required to be conventionally secured to an underlying support shank.

In another aspect, the bit body 20 comprises at least one particle-matrix composite material that is infiltrated by a binder material so that the at least one particle-matrix composite material is fully infiltrated by and is substantially encapsulated by the binder material to form a substantially uniform particle grain microstructure. In one aspect, each particle-matrix composite material has a particle material composition that has a particle material melting temperature. In another aspect, the binder material has a binder material composition that has a binder material melting temperature that is lower than the particle material melting temperature. Further, the particle material composition and the binder material composition are different material compositions.

It is contemplated that at least one of the particle-matrix material composition and the binder material composition is comprised of a matrix material and a plurality of hard particles dispersed throughout the matrix materials. The plurality of hard particles can be dispersed substantially randomly throughout the matrix material. In another aspect, each particle-matrix composite material is substantially comprised of the matrix material having the plurality of hard particles dispersed throughout.

In a further aspect, the binder material can comprises a second particle-matrix composite material. In this aspect, the second particle-matrix composite material is substantially comprised of a matrix material having a plurality of hard particles dispersed throughout. In a further aspect, the binder material can comprises non-magnetic materials and/or wear resistant materials. Similarly, the matrix material in the particle-matrix composition material can comprise non-magnetic materials and/or wear resistant materials. In one aspect, it is contemplated that the formed drill bit would be entirely formed from non-magnetic materials and/or wear resistant materials.

The matrix material of the binder composite material may include, for example, cobalt-based, iron-based, nickel-based, iron and nickel-based, cobalt and nickel-based, iron and cobalt-based, aluminum-based, copper-based, magnesium-based, molybdenum based, and titanium-based alloys. The alloying elements can include, but are not limited to, one or more of the following elements—manganese (Mn), nickel (Ni), tin (Sn) zinc (In), silicon (Si), molybdenum (Mo), tungsten (W), boron (B) and phosphorous (P). The matrix material of the binder composite material can also be selected from commercially pure elements such as cobalt, aluminum, copper, magnesium, titanium, iron, and nickel. By way of example and not limitation, the matrix material of the binder composite material may include carbon steel, alloy steel, stainless steel, tool steel, Hadfield manganese steel, nickel or cobalt superalloy material, and low thermal expansion iron or nickel based alloys.

The hard particles can comprise the hard particles can comprise diamond, or metal or semi-metal carbides, nitrides, oxides, or borides. For example, and without limitation, the hard particles can comprise diamond or ceramic materials such as carbides, nitrides, oxides, and borides (including boron carbide (B₄C)) and combinations of them, such as carbonitrides. More specifically, the hard particles can comprise carbides and borides made from elements such as W, Ti, Mo, Nb, V, Hf, Ta, Cr, Zr, Al, and Si. By way of example and without limitation, materials that may be used to form hard particles include tungsten carbide (WC, W₂C), titanium carbide (TiC), tantalum carbide (TaC), titanium diboride (TiB₂), chromium carbides, titanium nitride (TiN), vanadium carbide (VC), aluminium oxide (Al₂O₃), aluminium nitride (AlN), boron nitride (BN), and silicon carbide (SiC). Furthermore, combinations of different hard particles may be used to tailor the physical properties and characteristics of the particle-matrix composite material. The hard particles may be formed using techniques known to those of ordinary skill in the art. Most suitable materials for hard particles are commercially available and the formation of the remainder is within the ability of one of ordinary skill in the art.

In one example, and not meant to be limiting, the matrix of the particle-matrix composite composition can comprise a tungsten-based alloy and the matrix of the binder material composition can be selected from a group comprising a copper based alloy, a zinc based alloy, and a nickel based alloy. In a further example, and not meant to be limiting, the matrix of the particle-matrix composite composition can comprise a tungsten carbide-based alloy and the matrix of the binder material composition can be selected from a group comprising a copper based alloy, a zinc based alloy, and a nickel based alloy. The use of tungsten and or tungsten carbide is desirable for use because of its higher hardness, which allows the use of smaller particles due to its high melting point, and suitability for use in an infiltration process because of the generally shorter times at high temperature prior to solidification and cooling of the matrix materials (in contrast with other methods of making a particle-matrix composite materials such as various powder metallurgy processes, such as sintering, that typically employ much longer times at high temperatures).

Because the binder material has a binder material composition that has a binder material melting temperature that is lower than the particle material melting temperature, the at least one particle-matrix composite material is in an unmelted state in the formed substantially uniform particle grain microstructure of the drill bit. When formed, it is desired that the particle-matrix composite material is substantially encapsulated by the infiltrated binder material. Further, to accomplish the desired infiltration without melting of the particle-matrix composite composition, the difference between the binder material melting temperature and the particle material melting temperature is greater than 500° F., preferably greater than 1000° F., and more preferred being greater than 1,500° F.

In a further aspect, and as shown in FIG. 2, it is further contemplated that the at least one particle-matrix composite material can comprise a plurality of particle-matrix composite materials. In this aspect, each particle-matrix composite material can be disposed in a layer positioned transverse to a longitudinal axis of the bit body. This layered approach allows for a fully infiltrated bit body using a common binder material that can have separate desired mechanical properties for the respective layers.

Although several embodiments of the invention have been disclosed in the foregoing specification, it is understood by those skilled in the art that many modifications and other embodiments of the invention will come to mind to which the invention pertains, having the benefit of the teaching presented in the foregoing description and associated drawings. It is thus understood that the invention is not limited to the specific embodiments disclosed hereinabove, and that many modifications and other embodiments are intended to be included within the scope of the appended claims. Moreover, although specific terms are employed herein, as well as in the claims which follow, they are used only in a generic and descriptive sense, and not for the purposes of limiting the described invention, nor the claims which follow. 

What is claimed is:
 1. A rotary drill bit, comprising: a bit body having a distal cutting region configured to engage a subterranean earth formation and a proximal treaded region configured to be selectively coupled to a drill sting, the bit body comprising: at least one particle-matrix composite material, each particle-matrix composite material having a particle material composition that has a particle material melting temperature, and a binder material having a binder material composition differing from the particle material composition and having a binder material melting temperature that is lower than the particle material melting temperature, wherein at least one of the particle-matrix material composition and the binder material composition is comprised of a matrix material and a plurality of hard particles dispersed throughout the matrix materials, and wherein the binder material is infiltrated within the particle-matrix material to form a substantially uniform particle grain microstructure.
 2. The rotary drill bit of claim 1, wherein each particle-matrix composite material is substantially comprised of the matrix material having the plurality of hard particles dispersed throughout.
 3. The rotary drill bit of claim 2, wherein the binder material comprises a second particle-matrix composite material.
 4. The rotary drill bit of claim 3, wherein the binder material is substantially comprised of a matrix material having a plurality of hard particles dispersed throughout.
 5. The rotary drill bit of claim 4, wherein the binder material comprises copper (Cu), nickel (Ni), cobalt (Co), iron (Fe), molybdenum (Mo) individually or alloys based on these metals.
 6. The rotary drill bit of claim 4, wherein the binder material comprises non-magnetic materials.
 7. The rotary drill bit of claim 4, wherein the binder material comprises wear resistant materials.
 8. The rotary drill bit of claim 4, wherein the hard particles comprise diamond, or metal or semi-metal carbides, nitrides, oxides, or borides.
 9. The rotary drill bit of claim 5, wherein the matrix materials comprise cobalt-based alloys, iron-based alloys, nickel-based alloys, cobalt and nickel-based alloys, iron and nickel-based alloys, iron and cobalt-based alloys, aluminum-based alloys, copper-based alloys, magnesium-based alloys, tungsten-based and titanium-based alloys.
 10. The rotary drill bit of claim 2, wherein the matrix material in the particle-matrix composite material comprises non-magnetic materials.
 11. The rotary drill bit of claim 2, wherein the matrix material in the particle-matrix composite material comprises wear resistant materials.
 12. The rotary drill bit of claim 1, wherein the binder material comprises a second particle-matrix composite material.
 13. The rotary drill bit of claim 12, wherein the binder material is substantially comprised of the matrix material having the plurality of hard particles dispersed throughout.
 14. The rotary bit of claim 1, wherein the at least one particle-matrix composite material is in an unmelted state in the formed substantially uniform particle grain microstructure.
 15. The rotary bit of claim 1, wherein the at least one particle-matrix composite material comprises a plurality of particle-matrix composite materials, and wherein each particle-matrix composite material is disposed in a layer positioned transverse to a longitudinal axis of the bit body.
 16. The rotary drill bit of claim 4, wherein the matrix of the particle-matrix composite composition comprises a tungsten-based alloy.
 17. The rotary drill bit of claim 16, wherein the matrix of the binder material composition is selected from a group comprising a copper-based alloy, a zinc-based alloy, and a nickel-based alloy.
 18. The rotary drill bit of claim 4, wherein the matrix of the particle-matrix composite composition comprises a tungsten carbide-based alloy.
 19. The rotary drill bit of claim 18, wherein the matrix of the binder material composition is selected from a group comprising a copper-based alloy, a zinc-based alloy, and a nickel-based alloy.
 20. The rotary drill bit of claim 1, wherein the proximal treaded region defines an open internal cavity extending along a longitudinal axis of the bit body, and wherein a helical thread is formed on an interior wall surface of the open internal cavity, the helical thread being configured matingly engage and attach to the drill string.
 21. The rotary drill bit of claim 1, wherein the proximal treaded region defines an exterior surface, and wherein a helical thread is formed on at least a portion of the exterior surface, the helical thread being configured matingly engage and attach to the drill string.
 22. The rotary drill bit of claim 1, wherein the particle-matrix composite material is substantially encapsulated by the infiltrated binder material.
 23. The rotary drill bit of claim 1, wherein the difference between the binder material melting temperature and the particle material melting temperature is greater than 500° F.
 24. The rotary drill bit of claim 1, wherein the difference between the binder material melting temperature and the particle material melting temperature is greater than 1000° F.
 25. The rotary drill bit of claim 1, wherein the difference between the binder material melting temperature and the particle material melting temperature is greater than 1,500° F. 